This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Chronic hepatitis C virus-HCV infection is a global health problem as it affects an estimated 170 million individuals worldwide. In the United States, the prevalence of HCV infection in the pediatric population, under or equal to 18 years old, is estimated to be 0.1-0.2 percent as compared to 1.8 percent in adults. Thus, there are approximately 150,000 children and 3.9 million adults chronically infected with HCV in the United States. The importance of HCV infection lies in its propensity to cause insidiously progressive liver damage. Sustained virologic response, defined by undetectable HCV RNA in serum 24 weeks after completion of treatment, occurs in approximately 36 percent of children treated with conventional interferon alone and in about 50 percent of those given conventional interferon in combination with ribavirin. Pegylated interferon-based treatment regimens are better than those based on conventional interferon in adults but little is known about peginterferons in children. The purpose of this study is to assess the efficacy and safety of peginterferon alfa-2a alone or in combination with ribavirin in pediatric patients with chronic hepatitis C.